kern/amd64: boot: Disable the i8259 chip on boot

To avoid interrupt conflicts on some machines with the I/O APIC, disable
the legacy i8259 chip by default

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/src/sys/include/arch/amd64/i8259.h b/src/sys/include/arch/amd64/i8259.h
new file mode 100644
index 0000000..29fc7dc
--- /dev/null
+++ b/src/sys/include/arch/amd64/i8259.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and L5 engineers
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MACHINE_I8259_H_
+#define _MACHINE_I8259_H_ 1
+
+#include <sys/cdefs.h>
+#include <machine/pio.h>
+
+/* Master/slave I/O base addresses */
+#define PIC1_BASE   0x20
+#define PIC2_BASE   0xA0
+
+/* Master/slave I/O command bases */
+#define PIC1_CMD    PIC1_BASE
+#define PIC2_CMD    PIC2_BASE
+
+#define PIC1_DATA   (PIC1_BASE + 1)
+#define PIC2_DATA   (PIC2_BASE + 1)
+
+/*
+ * Disable the i8259 interrupt controller by masking
+ * each and every pin.
+ */
+void i8259_disable(void);
+
+#endif  /* !_MACHINE_H_ */